The sources, with deep Cuomo administration ties, said the governor hatched the plan after becoming obsessed with the possibility that upstate opposition endangered his chances for topping dad Mario Cuomo’s historic first re-election victory margin in 1986, when he won with 65 percent of the vote.

“The governor has been crazed by his declining numbers upstate and was running around saying, ‘We have to have something for next year, we have to have something,’ and that’s how we got Tax Free NY,’’ said a Cuomo administration source.

Cuomo’s standing with upstate voters plunged in early January after he rammed the anti-gun ownership SAFE Act through the Legislature.

About a month earlier, in late November 2012, a Siena College poll had found traditionally Republican upstate residents strongly backing Democrat Cuomo’s reelection, 57-34 percent.

But just a few days after the SAFE Act’s passage, Cuomo’s upstate numbers began a notable erosion — to the point where last month just 41 percent of upstaters told Siena that Cuomo deserved re-election, while 50 percent said he did not.

“There’s no question the SAFE Act had a dramatic effect on how upstate voters view the governor,” said Siena pollster Steve Greenberg.

Cuomo started the year by saying he wanted legalized commercial gambling casinos upstate in order to help the region’s blighted economy (made worse by his refusal to authorize fracking for natural gas), but the plan met widespread skepticism, and there was no indication that it helped him with upstate voters.

So that was why Cuomo, in a last-ditch effort to turn things around before the Legislature recess for the summer, unveiled Tax Free NY just two weeks ago, with no advance notice, with no studies or projections to suggest its effectiveness and, so far, without the full endorsement of the Legislature’s leaders, insiders said.

While Cuomo has rounded up several prominent business and civic groups to support the plan — which would grant sweeping tax relief, including a waiver of personal income taxes, to new businesses that locate at SUNY towns and other college campuses — the pressure to win their support has been enormous.

“Cuomo’s people are leaning on everyone, telling them they have to support this publicly, even though many think it’s a bad idea that discriminates against all those businesses that won’t get these breaks,’’ said a prominent business figure.

Another business figure called the chances of Cuomo’s plan having a positive impact on the upstate economy “next to zero.”

Political experts told The Post that unless Cuomo turns around upstate anger, he could lose 55 or more of the state’s 62 counties next year and fall well below Mario Cuomo’s 65 percent.